U.S. patent number 10,594,246 [Application Number 15/854,096] was granted by the patent office on 2020-03-17 for board-level motor control system with integrated protection and control components.
This patent grant is currently assigned to Eaton Intelligent Power Limited. The grantee listed for this patent is Eaton Corporation. Invention is credited to Joshua B. Gross, Huaqiang Li, Thomas M. Ruchti, Joseph Paul Uphaus, Kaijam M. Woodley.
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United States Patent |
10,594,246 |
Li , et al. |
March 17, 2020 |
Board-level motor control system with integrated protection and
control components
Abstract
A motor control system for selectively controlling power from a
power source to a load is provided. The motor control system
includes at least one PCB structure and a plurality of protection
and control components mounted onto the at least one PCB structure
so as to be electrically coupled therewith. The plurality of
protection and control components includes a power converter
operable to provide a controlled output power to the load, a
plurality of switching devices operable to selectively control
power flow from the power source into the power converter and to
bypass the power converter, and one or more protection devices
configured to selectively interrupt current flow from the power
source to the power converter during a fault condition. The motor
control system also includes a housing enclosing the at least one
PCB structure and the plurality of protection and control
components.
Inventors: |
Li; Huaqiang (Menomonee Falls,
WI), Gross; Joshua B. (Cranberry, PA), Uphaus; Joseph
Paul (Whitefish Bay, WI), Ruchti; Thomas M. (Pewaukee,
WI), Woodley; Kaijam M. (Brown Deer, WI) |
Applicant: |
Name |
City |
State |
Country |
Type |
Eaton Corporation |
Cleveland |
OH |
US |
|
|
Assignee: |
Eaton Intelligent Power Limited
(Dublin, IE)
|
Family
ID: |
65009656 |
Appl.
No.: |
15/854,096 |
Filed: |
December 26, 2017 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20190199263 A1 |
Jun 27, 2019 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02P
27/045 (20130101); H02M 7/53875 (20130101); H05K
1/0257 (20130101); H02H 9/04 (20130101); H02M
5/458 (20130101); H02H 9/02 (20130101); H02M
7/003 (20130101); H02H 7/0822 (20130101); H02H
3/083 (20130101); H02H 9/001 (20130101); H02H
7/1225 (20130101); H02H 5/041 (20130101); H02P
27/04 (20130101) |
Current International
Class: |
H02P
27/04 (20160101); H02H 9/04 (20060101); H02M
7/5387 (20070101); H02H 7/08 (20060101); H05K
1/02 (20060101); H02H 9/02 (20060101) |
Field of
Search: |
;318/727 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"PowerGate `H` HVAC Bypass Controller," Mitsubishi Electric
Corporation, Feb. 2, 2017, pp. 1-2,
https://us.mitsubishielectric.com/fa/en/solutions/industries/hvac/powerga-
tehseries. cited by applicant.
|
Primary Examiner: Carrasquillo; Jorge L
Assistant Examiner: Joseph; Devon A
Attorney, Agent or Firm: Ziolkowski Patent Solutions Group,
SC
Claims
What is claimed is:
1. A motor control system for selectively controlling power from a
power source to a load, the motor control system comprising: at
least one printed circuit board (PCB) structure; and a plurality of
protection and control components mounted onto the at least one PCB
structure so as to be electrically coupled therewith, the plurality
of protection and control components comprising: a power converter
operable to provide a controlled output power to the load; a
plurality of switching devices operable to selectively control
power flow from the power source into the power converter and to
bypass the power converter; and one or more protection devices
configured to selectively interrupt current flow from the power
source to the power converter during a fault condition; and a
housing enclosing the at least one PCB structure and the plurality
of protection and control components.
2. The motor control system of claim 1 wherein the housing is
environmentally rated for the motor control system, and wherein
each of the plurality of protection and control components is free
of a discrete, environmentally rated housing.
3. The motor control system of claim 1 further comprising a control
system configured to control operation of the power converter and
the plurality of switching devices, the control system programmed
to control switching of the plurality of switching devices between
On and Off states to selectively route power to the power converter
and bypass the power converter.
4. The motor control system of claim 3 wherein the at least one PCB
structure comprises a substrate and a plurality of conductive
traces formed on the substrate, with the plurality of conductive
traces forming electrical connections between the plurality of
protection and control components and the control system.
5. The motor control system of claim 3 further comprising a control
panel coupled to the at least one PCB structure, the control panel
comprising a user interface configured to receive inputs from a
user and provide the inputs to the control system.
6. The motor control system of claim 5 wherein the housing
comprises a front door; and wherein the user interface is
accessible to the user through an opening formed in the front door
when the front door is in a closed position.
7. The motor control system of claim 3 wherein the control system
and the plurality of protection and control components are powered
by the power source.
8. The motor control system of claim 1 wherein the plurality of
protection and control components comprise plug-and-play components
that clip onto the at least one PCB structure.
9. The motor control system of claim 1 wherein the plurality of
protection and control components are soldered directly onto the at
least one PCB structure.
10. The motor control system of claim 1 further comprising one or
more thermal management devices that provide system-level thermal
management for the motor control system, with shared cooling of the
power converter and the plurality of switching devices.
11. The motor control system of claim 1 wherein the one or more
protection devices comprises one or more of: an input fuse that
provides overcurrent protection to the power converter and the
plurality of switching devices, the input fuse mounted on the at
least one PCB structure; and a disconnect contactor operable to
disconnect the motor control system from the power source, the
disconnect contactor configured to interface with the at least one
PCB structure.
12. The motor control system of claim 1 wherein the plurality of
switching devices integrated onto the at least one PCB structure
comprises: an input relay positioned upstream of the power
converter to control power flow into the power converter; an output
relay positioned downstream of the power converter to control power
flow output from the power converter; and a solid-state switching
device comprising a plurality of solid-state switches that are
selectively switchable to control and condition power flow
therethrough, the solid-state switching device arranged upstream
from the input relay or in parallel with the input relay.
13. The motor control system of claim 12 wherein the solid-state
switching device functions as an overload relay when overvoltage
and/or overcurrent conditions are present in the motor control
system.
14. A motor control system for selectively controlling power from a
power source to a load, the motor control system comprising: a
printed circuit board (PCB) structure comprising at least one
substrate and a plurality of conductive traces formed on the at
least one substrate; a motor switching assembly integrated onto the
PCB structure, the motor switching assembly comprising: a power
converter operable to provide a controlled output power to the
load; and a plurality of switching devices operable to selectively
control power flow from the power source into the power converter
and to bypass the power converter; and a controller coupled to the
PCB structure and configured to control operation of the power
converter and the plurality of switching devices; wherein the
conductive traces form electrical connections within the motor
switching assembly and electrically connect the motor switching
assembly to the controller.
15. The motor control system of claim 14 further comprising an
environmentally rated housing that encloses the PCB structure, the
motor switching assembly, and the controller, and wherein the power
converter, the plurality of switching devices, and the controller
are each free of a discrete, environmentally rated housing.
16. The motor control system of claim 14 wherein the power
converter and the plurality of switching devices comprise
plug-and-play components that snap onto the PCB structure.
17. The motor control system of claim 14 wherein the power
converter and the plurality of switching devices comprise
components that are soldered directly onto the PCB structure.
18. The motor control system of claim 14 further comprising a heat
sink mounted to the power converter and a solid-state switching
unit of the plurality of switching devices to provide shared
cooling thereto.
19. A method of manufacturing a board-level motor control system
for controlling power from a power source to a load, the method
comprising: providing a printed circuit board (PCB) structure
comprising at least one substrate and a plurality of conductive
traces formed on the at least one substrate; mounting a plurality
of protection and control components onto the PCB structure,
wherein mounting the plurality of protection and control components
comprises one of: snapping respective plug-and-play components of
the plurality of protection and control components onto the PCB
structure; and soldering respective components of the plurality of
protection and control components onto the PCB structure;
electrically connecting the plurality of protection and control
components via the plurality of conductive traces; and operatively
connecting a controller to the plurality of protection and control
components, with the plurality of conductive traces providing at
least a portion of electrical connections between the controller
and the plurality of protection and control components, mounting a
power converter onto the PCB structure that is operable to provide
a controlled output power to the load; and mounting one or more
additional protection and control components onto the PCB
structure, the one or more additional protection and control
components comprising one or more of: an input relay positioned
upstream of the power converter to control power flow into the
power converter; an output relay positioned downstream of the power
converter to control power flow output from the power converter;
and a solid-state switching device comprising a plurality of
solid-state switches that are selectively switchable to control and
condition power flow therethrough, the solid-state switching device
arranged upstream from the input relay or in parallel with the
input relay.
20. The method of claim 19 wherein mounting the plurality of
protection and control components comprises: mounting a power
converter onto the PCB structure that is operable to provide a
controlled output power to the load; and mounting one or more
additional protection and control components onto the PCB
structure, the one or more additional protection and control
components comprising one or more of: an input relay positioned
upstream of the power converter to control power flow into the
power converter; an output relay positioned downstream of the power
converter to control power flow output from the power converter;
and a solid-state switching device comprising a plurality of
solid-state switches that are selectively switchable to control and
condition power flow therethrough, the solid-state switching device
arranged upstream from the input relay or in parallel with the
input relay.
Description
BACKGROUND OF THE INVENTION
Embodiments of the invention relate generally to motor control
systems and, more particularly, to a board-level motor control
system having integrated protection and control components.
One type of system commonly used in industry that performs power
conversion is an adjustable speed drive, also known as a variable
frequency drive (VFD). A VFD is an industrial control device that
provides for variable frequency, variable voltage operation of a
driven system, such as an AC induction motor. In use, a VFD is
often provided as part of a motor control system and overall
control and protection assembly that includes the VFD as well as an
arrangement of input/output fuses, disconnects, circuit breakers or
other protection devices, controllers, filters, sensors, and a
bypass assembly that includes one or more of a bypass contactor and
soft starter that provide alternate control paths or mechanisms for
controlling the driven system.
As a general rule in known motor control systems, the VFD and
associated protection and control devices, generally indicated as
components 2 in FIG. 1, are provided as discrete components having
their own housings 4. The discrete, housed components 2 are
positioned within a large metal enclosure 6. The arrangement of
components 2 is fixed to a support within the enclosure 6, such as
a DIN rail for example, with wiring 8 being provided between the
components 2 to provide for electrical connectivity and/or
communication therebetween. When the overall collection of
components 2 is assembled as a unit, the enclosure 6 required to
house the components 2 becomes quite large and bulky. Also, the
large amount of wiring 8 required between the components 2 can
hinder accessibility to the components 2, increases installation
time and the potential for failure due to wiring and wiring
connections, and reduces the overall efficiency of the motor
control system.
It would therefore be desirable to provide a motor control system
with a minimized footprint, increased efficiency, improved
operational flexibility, and the ability for shared thermal
management for multiple components.
BRIEF DESCRIPTION OF THE INVENTION
In accordance with one aspect of the invention, a motor control
system for selectively controlling power from a power source to a
load is provided. The motor control system includes at least one
printed circuit board (PCB) structure and a plurality of protection
and control components mounted onto the at least one PCB structure
so as to be electrically coupled therewith. The plurality of
protection and control components includes a power converter
operable to provide a controlled output power to the load, a
plurality of switching devices operable to selectively control
power flow from the power source into the power converter and to
bypass the power converter, and one or more protection devices
configured to selectively interrupt current flow from the power
source to the power converter during a fault condition. The motor
control system also includes a housing enclosing the at least one
PCB structure and the plurality of protection and control
components.
In accordance with another aspect of the invention, a motor control
system for selectively controlling power from a power source to a
load, is provided. The motor control system includes a PCB
structure comprising at least one substrate and a plurality of
conductive traces formed on the at least one substrate and a motor
switching assembly integrated onto the PCB structure. The motor
switching assembly further includes a power converter operable to
provide a controlled output power to the load and a plurality of
switching devices operable to selectively control power flow from
the power source into the power converter and to bypass the power
converter. The motor control system also includes a controller
coupled to the PCB structure and configured to control operation of
the power converter and the plurality of switching devices. The
conductive traces form electrical connections within the motor
switching assembly and electrically connect the motor switching
assembly to the controller.
In accordance with yet another aspect of the invention, a method of
manufacturing a board-level motor control system for controlling
power from a power source to a load is provided. The method
includes providing a PCB structure comprising at least one
substrate and a plurality of conductive traces formed on the at
least one substrate and mounting a plurality of protection and
control components onto the PCB structure, wherein mounting the
plurality of protection and control components comprises one of
snapping respective plug-and-play components of the plurality of
protection and control components onto the PCB structure and
soldering respective components of the plurality of protection and
control components onto the PCB structure. The method also includes
electrically connecting the plurality of protection and control
components via the plurality of conductive traces.
Various other features and advantages of the present invention will
be made apparent from the following detailed description and the
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings illustrate preferred embodiments presently
contemplated for carrying out the invention.
In the drawings:
FIG. 1 is a schematic view of a motor control system as known in
the prior art.
FIG. 2 is a block diagram of a board-level motor control system,
according to an embodiment of the invention.
FIGS. 3A and 3B are perspective views of the board-level motor
control system of FIG. 2, according to an embodiment of the
invention.
FIG. 4 is a schematic diagram of a motor switching assembly
included in the motor control system of FIG. 2 and FIGS. 3A and 3B,
according to an embodiment of the invention.
FIG. 5 is a perspective view of a compact housing enclosing the
motor control system of FIG. 2 and FIGS. 3A and 3B, according to an
embodiment of the invention.
FIG. 6 is a schematic diagram of a motor switching assembly,
according to another embodiment of the invention.
DETAILED DESCRIPTION
Embodiments of the invention relate to a compact, board-level motor
control system. The board-level motor control system has integrated
solid-state contactors, drives, filters, and protection devices
(e.g., fuses) at a circuit board level, such that electrical
connections between the components can be made via electrical
traces on the board and without the use of separate cables or
wires. A single, compact plastic enclosure may be provided for the
board-level motor control system that replaces the typical bulky
metal enclosure and individual component housings that are found in
existing motor control systems.
While embodiments of the invention are described and illustrated
herebelow as being directed to a motor control system, it is
recognized that embodiments of the invention are not meant to be
limited to such circuits. That is, embodiments of the invention may
be extended more generally to power/energy conversion circuits of
varying constructions and implementations, including motor
starters, motor control centers, and power/energy conversion
circuits for driving non-motor loads, for example. Accordingly, the
following discussion of a board-level motor control system is not
meant to limit the scope of the invention.
Referring to FIG. 2, a block schematic of a power system 10 is
shown. Power system 10 includes a power source 12, such as from a
utility, for example, coupled to a disconnect contactor or switch
14 that may be operated in a closed or On position in which power
from utility 12 is allowed to flow therethrough and an open or Off
position in which power may not flow therethrough. Power system 10
also includes an input fuse 16 coupled to disconnect switch 14.
Input fuse 16 provides overcurrent protection by interrupting the
current from utility 12 if the level of current becomes too high.
Input fuse 16 is coupled to (and may be considered part of) a motor
control system 18, which is then coupled to an optional output
filter 20 that helps protect a motor 22 (or other load) from the
harmful effects of reflected waves due to impedance mismatch and
prevent motor failure due to insulation failure, overheating, and
noise.
As shown in FIG. 2 and also now in FIGS. 3A and 3B, motor control
system 18 includes a motor switching assembly or module 24 and a
control system or controller 26 that provides control signals to
various components of motor switching assembly 24 (and may
optionally control the position of disconnect switch 14). According
to embodiments of the invention, the motor control system 18 is
provided as a board-level circuit, with the system including a
plurality of protection and control components/devices that are
mounted to or formed directly on a printed circuit board (PCB) 28.
The PCB 28 may be provided as a single board or as a modular board
(i.e., two or more distinct PCBs) and may have a standard or
customized construction. The PCB 28 includes an insulating
substrate 29 with a plurality of traces or leads 31 formed thereon
that provide electrical connection paths on the substrate 29
between components. The plurality of components included in motor
switching assembly 24 that are mounted to or formed on the PCB 28
provide for control and protection of motor 22 and may include,
without limitation, a power converter 30 and input, output, and
bypass switching devices or relays 34, 36, 38.
According to embodiments of the invention, the board-level
components 16, 30, 34, 36, 38 may be removably or fixedly mounted
on the PCB 28 according to alternative embodiments. In one
embodiment, some or all of components 16, 30, 34, 36, 38 are
provided with slot and/or pin type plug-and-play type attachment
components 32 (see FIGS. 3A and 3B) that snap onto or interfit with
mating plug-and-play type receptacles mounted on the PCB 28.
Alternatively, some or all of components 16, 30, 34, 36, 38 are
permanently soldered to the PCB 28. The components 16, 30, 34, 36,
38 may be electrically connected to the PCB 28 via contact pads on
the PCB 28 that mate with or are soldered to corresponding pads on
the respective components. Regardless of whether components 16, 30,
34, 36, 38 are removably or fixedly mounted to PCB 28, electrical
connections and communications between the components 16, 30, 34,
36, 38 (and controller 26) may be provided via the traces 31 formed
on the PCB 28 substrate. This mounting of components 16, 30, 34,
36, 38 directly to PCB 28 and use of electrical traces 31 to form
connections between components results in a board-level motor
switching assembly 24 having fewer terminal connections and cables,
such that voltage losses in the motor switching assembly 24 are
reduced and efficiency of the board is improved.
As shown in FIG. 4, one embodiment of motor control system 18
includes a power converter 30 in the form of a VFD unit (hereafter
"VFD unit 30") that provides for driving and adjusting the
operating speed of motor 22. VFD unit 30 may be of known
construction that may generally include: a rectifier bridge 42 that
converts an AC input power into a DC power, a DC link 44 that
receives the DC power from the rectifier bridge, a DC link
capacitor bank 46 across DC link, and optional inductors 48 coupled
in series with and on either side of the rectifier bridge 42 on DC
link 44 (i.e., a DC choke). The VFD unit 30 may also include an
inverter 50 to convert the DC power to AC power--with the inverter
50 being comprised of a plurality of solid-state switches 52 (e.g.,
IGBTs) that may be selectively controlled to output a desired
three-phase, three line power from the VFD unit 30 and to the motor
22. While not shown in FIG. 4, it is recognized that input and EMI
filters may be provided with VFD unit 30. The three-phase power
output by VFD unit 30 is regulated/controlled by controller 26 via
the transmission of gate drive signals to the inverter switches 52
to control opening and closing thereof, thereby controlling the
current flow (and therefore the voltage) applied to the motor
22.
As further shown in FIG. 4, the input, output, and bypass switching
devices 34, 36, 38 may be configured as solid-state type switching
devices or as electromechanical switches. In the embodiment of FIG.
4, input and output switching devices 34, 36 are shown as
electromechanical relays/contactors, while bypass switching device
38 is shown as a solid-state switching device that includes a pair
of anti-parallel solid-state switches 56 on each phase 58, such as
solid-state switches in the form of silicon controlled rectifiers
(SCRs) or thyristors that control the current flow through bypass
switching device 38 and provide for a "soft-starter" functionality.
The electromechanical input and output relays 34, 36 may thus be
operated in an On/closed state to conduct current therethrough and
an Off/open state to block current therethrough, while solid-state
switches 56 of bypass switching device 38 may be operated an
On/closed state to conduct current therethrough, an Off/open state
to block current therethrough, or selectively switched On/Off to
control transmission of voltage and current therethrough and
thereby limit the transient voltages and current to the motor
22--allowing for a soft ramp-up of the motor 22. Solid-state
switches 56 further allow controller 26 to control bypass switching
device 38 as an overload relay based on overvoltage and/or
overcurrent conditions present in power system 10 (FIG. 2).
In operation of motor control system, controller 26 selectively
operates the motor switching assembly 24 in what are termed herein
as a VFD mode (i.e., power conversion mode) or a bypass mode of
operation, with power being provided to motor 22 through VFD unit
30 in the VFD mode of operation and power being provided to motor
22 through a bypass path 40 (with VFD unit 30 disconnected) in the
bypass mode of operation. In the case of an inverter fault, over
temperature fault, or other error in the VFD unit 30, motor
operation can be automatically transferred to the bypass path 40 to
continue operation of the motor 22, maintain drive life, and for
other benefits. The controller 26 may also determine to transfer
motor operation to the bypass path 40 when it is desired to operate
the motor 22 in a steady-state condition (e.g., full speed) that
does not require power conditioning by the VFD unit 30, such that
bypassing thereof might be beneficially employed to reduce
switching losses, etc.
In controlling operation of motor switching assembly 24 in the VFD
mode and bypass mode of operation, controller 26 controls operation
of switching devices 34, 36, 38 via the opening and closing of
mechanical contacts or solid-state switches thereof, such as via
the transmission of control signals or gate drive signals thereto.
By controlling opening and closing of switching devices 34, 36, 38,
current through the VFD unit 30 can be selectively controlled. More
specifically, the input relay 34 and output relay 36 provide for
current flow through VFD unit 30 when in an On/closed state or
position and do not allow current flow through VFD unit 30 when in
an Off/open state or position (instead electrically isolating the
VFD unit 30 from power source 12 and motor 22), while the bypass
switching device 38 provides for current flow through bypass path
40 when SCRs 56 are in an On/closed state or position and diverts
current away from the bypass path 40 when SCRs 56 are in an
Off/open state or position. It is recognized that bypass switching
device 38 will be controlled to be in the Off state when input and
output relays 34, 36 are in the On position (with this being the
VFD mode of operation of motor switching assembly 24) and that
bypass switching device 38 will be controlled to be in the On state
when input and output relays 34, 36 are in the Off position (with
this being the bypass mode of operation of motor switching assembly
24).
According to embodiments of the invention, the controller 26 may
make a determination of whether to operate the motor switching
assembly 24 in the VFD mode or the bypass mode of operation based
on a number of inputs and/or measured parameters. In one
embodiment, the controller 26 may make the determination of whether
to operate motor switching assembly 24 in VFD mode or bypass mode
based upon one or more inputs by an operator indicating that the
motor 22 is to be operated in a steady-state condition (e.g., at
full speed) that does not require power conditioning by the VFD
unit 30, such that bypassing thereof might be beneficially employed
(e.g., to reduce switching losses). In another embodiment, the
controller 26 may make this determination based upon detection that
the VFD unit 30 has experienced a fault condition or is otherwise
not functioning properly. That is, controller 26 may compare one or
more voltage and/or current values measured in the VFD unit 30, as
inputs to the VFD unit, or as outputs from the VFD unit (such as
measured by voltage and/or current sensors or sensing circuits 60
(FIG. 2), for example), to one or more pre-defined thresholds in
order to sense a short circuit or other fault condition in the
motor switching assembly. For example, one or more voltage or
current sampling or sensing circuits or sensors 60 may operate to
measure one or more of the following voltage/current parameters in
the motor switching assembly, including: three phase input currents
or voltages to the VFD unit 30, current at the switch level of
rectifier 42 or inverter 50 and/or on DC link 44 in the VFD unit
30, and/or load output currents or voltages from the VFD unit 30,
for example. As one example, the controller 26 compares the DC link
voltage to a pre-defined "Overvoltage Condition" to determine if
the VFD unit 30 has malfunctioned.
Beneficially, integration of the switching devices 34, 36, 38 onto
PCB 28 at a board-level and the operability and control of the
switching devices 34, 36, 38 by controller 26 allows for
simplification of the motor switching assembly 24. That is, the
integration of the switching devices 34, 36, 38 onto PCB 28 at the
board-level eliminates the need for auxiliary devices that
sense/determine the state of switching devices/relays 34, 36, 38,
as such functionality or firmware is provided in controller 26.
Additionally, integration of the switching devices 34, 36, 38 onto
PCB 28 at the board-level allows for a single controller or central
processor to control operation of switching devices 34, 36, 38 and
VFD unit 30 based on inputs or sensed parameters provided to
controller 26, as described above. The board-level construction of
control system 18 and its singular controller 26 eliminates need
for multiple discrete control circuits or processors (e.g.,
overload processor and bypass processor) and/or a
micro-programmable multi-processor (MMP) of prior art topologies.
All sensor hardware, functions, and digital signal processing may
be built into the board-level motor control system 18, making an
overload relay and associated sensors and processors unnecessary
(i.e., a common current sense functionality for motor overload in
system 18).
In addition to the above, construction of motor control system 18
as a board-level circuit provides advantages regarding power supply
and thermal management. As one example, the board-level motor
control system 18 may derive control powers from input power
provided by utility source 12 (FIG. 2), as compared to typical
motor control system designs/products where a standalone,
commercially available power supply is required to provide control
power. As another example, construction of motor control system 18
as a board-level circuit allows for efficient system-level
temperature monitoring and management of the motor switching
assembly 24 via the use of one or more thermal management devices
62, 64, such as thermocouples for component temperature monitoring,
shared heat sinks for cooling of multiple board-mounted components
(e.g., heat sink 62 for cooling VFD unit 30 and solid-state bypass
switching device 38), and airflow generator(s) 64 (e.g., fan) to
manage airflow across the PCB 28 and components thereon.
As shown in FIGS. 3A and 3B, board-level components 16, 30, 34, 36,
38 are integrated onto PCB 28 without their own discrete,
environmentally rated enclosures or housings (e.g., National
Electrical Manufacturer Association (NEMA), Ingress Protection
(IP), and/or Underwriters Laboratories Inc. (UL)). Instead, motor
control system 18 is housed within a compact housing 66 (FIG. 5)
that provides protection for the components and meets environmental
ratings standards (i.e., ingress protection standards) for the
overall motor control system 18. Housing 66 is constructed from an
electrically non-conductive material such as, for example, plastic.
The size of the housing 66 is greatly reduced as compared to a
standard large metal enclosure (e.g., housing 6, FIG. 1) that
encloses a motor drive system having discrete protection and
control devices (each with its own housing and being connected via
cabling). For example, the compact plastic housing 66 of motor
control system 18 may have dimensions of
20.5''.times.8''.times.10.25'', as compared to a standard large
metal enclosure having dimensions of
36''.times.20.5''.times.12.00''.
According to one embodiment, housing 66 may be formed with an
opening 68 in a front door 70 thereof to accommodate a
human-machine interface (HMI) or control panel 72 of the motor
control system 18. As shown in FIGS. 3A and 3B and FIG. 5, the
control panel 72 is mounted directly to PCB 28 and may extend out
therefrom to fit within opening 68, so as to be accessible by a
user even when front door 70 is closed. The control panel 72 may
facilitate installation, operation, maintenance, or other
interactions with the motor control system 18. The control panel 72
includes a user interface 74 that, may include hands-off-auto
selector buttons, a touch screen LCD display, a jumper/selector
switch, indicator lights, and/or connection ports or I/Os for
connecting external electronic devices (e.g., laptop or other
mobile computing and networking devices) for fast setup or remote
monitoring purposes (i.e., receiving outputs from motor control
system 18), to name but a few non-limiting examples. Of course
those skilled in the relevant art will appreciate that additional,
fewer, or alternative user interface components could be employed
without departing from the scope of the present subject matter.
Additional embodiments of the invention may also provide for
alternative means of communicating with the motor control system
18, such as by providing for wireless communication with the motor
control system 18 over a local network/server or via a cloud-based
system/platform--generally designated as "communication 76" in FIG.
2. Monitoring or control of the motor control system 18 may be
achieved via a remote device (e.g., laptop or other mobile
computing and networking devices), with the remote device being
able to access any combination of digital or analog signals from
the motor control system 18 indicating a current state of the
components thereof and their associated processes (e.g.,
operational mode, fault status, diagnostics, temperature, etc.).
According to one embodiment, motor control system 18 can be coupled
to a cloud platform 76 to leverage cloud-based applications and
services. That is, the motor control system 18 can be configured to
interact with cloud-based computing services hosted by cloud
platform 76. Cloud platform 76 can be any infrastructure that
allows shared computing services to be accessed and utilized by
cloud-capable devices. Cloud platform 76 can be a public or private
cloud accessible via the Internet by a motor control system 18
having Internet connectivity and appropriate authorizations to
utilize the services. Cloud services can include, but are not
limited to, data storage, data analysis, control applications
(e.g., applications that can generate and deliver control
instructions to motor control system 18 based on analysis of near
real-time system data or other factors), system management
applications, or other such applications. If cloud platform 76 is a
web-based cloud, motor control system 18 may interact with cloud
services via the Internet. In an exemplary configuration, motor
control system 18 may access the cloud services through a cloud
gateway, where the motor control system 18 connect to the cloud
gateway through a physical or wireless local area network or radio
link or through an integrated cloud gateway service.
Referring now to FIG. 6, an additional embodiment of a board-level
motor control system 18 is illustrated where motor control assembly
24 includes a modified arrangement of protection and control
components thereon. In the embodiment of FIG. 6, the arrangement of
switching devices 34, 36, 38 illustrated in FIG. 4 is replaced with
an arrangement of a solid-state switching unit 76 and lower rated
input, output and bypass relays 78, 80, 82. With regard to
solid-state switching unit 76, the unit includes a pair of
anti-parallel switches 56 (e.g., SCRs or thyristors) on each supply
line of the three-phase input that are selectively switched to
control the current flow through solid-state switching unit--with
switches 56 being selectively controlled to conduct current
therethrough, block current, or to provide a controlled power
output to enable a ramping or soft-starting of motor. With regard
to the input relay 78, output relay 80, and bypass relay 82, the
relays may 78, 80, 82 be provided as electro-mechanical or solid
state relays that have a rating lower than a full motor voltage
rating and lower than inrush current ratings. That is, as can be
seen in FIG. 6, the solid-state switching unit 76 is positioned
upstream from input relay 78 and bypass relay 82 and from where
input power is directed to either the bypass path 40 or to VFD unit
30 based on controlling of the input relay 78 and bypass relay 82.
The positioning of solid-state switching unit 76 at a location
upstream from input and bypass relays 78, 82 allows for switching
of the input and bypass relays 78, 82 at a zero load condition, as
the SCRs 56 may be switched to an Off/non-conducting state for a
period during which the relays are switched. Accordingly, the
input, output, and bypass relays 78, 80, 82, may be in the form of
lower rated relays having a voltage rating that is less than a full
motor voltage of motor 22 and less than inrush current ratings.
Beneficially, embodiments of the invention thus provide a
board-level motor control system that integrates power conversion,
protection and control devices onto a PCB structure, thereby
eliminating wiring between discrete components so as to reduce
cable losses, require fewer terminal connections, and eliminate
voltage losses of those connections, such that a more efficient
motor control system is provided. The board-level motor control
system may derive control powers from input power provided by
utility source and provide for efficient temperature monitoring and
management of a motor switching assembly in the system. The
board-level motor control system may eliminate the need for
environmentally rated housing on individual components and instead
may be housed within a single compact plastic enclosure.
Integration of electromechanical and/or solid-state switching
devices into the board-level motor control system provides
electrical isolation and enables transitioning between operational
modes, with the integrated switching devices providing for
flexibility in routing power to a power converter or a bypass
around the power converter and transitioning between modes.
According to one embodiment of the present invention, a motor
control system for selectively controlling power from a power
source to a load is provided. The motor control system includes at
least one printed circuit board (PCB) structure and a plurality of
protection and control components mounted onto the at least one PCB
structure so as to be electrically coupled therewith. The plurality
of protection and control components includes a power converter
operable to provide a controlled output power to the load, a
plurality of switching devices operable to selectively control
power flow from the power source into the power converter and to
bypass the power converter, and one or more protection devices
configured to selectively interrupt current flow from the power
source to the power converter during a fault condition. The motor
control system also includes a housing enclosing the at least one
PCB structure and the plurality of protection and control
components.
According to another embodiment of the present invention, a motor
control system for selectively controlling power from a power
source to a load, is provided. The motor control system includes a
PCB structure comprising at least one substrate and a plurality of
conductive traces formed on the at least one substrate and a motor
switching assembly integrated onto the PCB structure. The motor
switching assembly further includes a power converter operable to
provide a controlled output power to the load and a plurality of
switching devices operable to selectively control power flow from
the power source into the power converter and to bypass the power
converter. The motor control system also includes a controller
coupled to the PCB structure and configured to control operation of
the power converter and the plurality of switching devices. The
conductive traces form electrical connections within the motor
switching assembly and electrically connect the motor switching
assembly to the controller.
According to yet another embodiment of the present invention, a
method of manufacturing a board-level motor control system for
controlling power from a power source to a load is provided. The
method includes providing a PCB structure comprising at least one
substrate and a plurality of conductive traces formed on the at
least one substrate and mounting a plurality of protection and
control components onto the PCB structure, wherein mounting the
plurality of protection and control components comprises one of
snapping respective plug-and-play components of the plurality of
protection and control components onto the PCB structure and
soldering respective components of the plurality of protection and
control components onto the PCB structure. The method also includes
electrically connecting the plurality of protection and control
components via the plurality of conductive traces.
The present invention has been described in terms of the preferred
embodiment, and it is recognized that equivalents, alternatives,
and modifications, aside from those expressly stated, are possible
and within the scope of the appending claims.
* * * * *
References